I tried that, but it didn't work.
This is what I do:
In the config, I change: "PALETTE = PICO8" and save.
Later in the console, I type "new" (for create new cartridge), then go to the sprite editor, and the palette didn't change. I tested with all other predefined palettes too, and it didn't work.
I'm doing something wrong?
I got the problem, seems default cartridge has DB16 palette and that's why you don't see changes.
So, it shouldn't be, it's a bug. As a temporary solution, load palette.tic from demos, copy any palette string from the code and paste it to the Palette Editor. (also, pls create an issue on the Github)